He noted that the OED included "prick" and paused to ask: "Why this further injustice to women?" His entry concludes with the haphazard yet enlightening quotation from some unnamed correspondent, who wrote to Partridge observing: "'Cunt' tends to mean 'knave' rather than 'fool'. Among the words left out of Oxford dictionaries were, notoriously, "fuck" and "cunt", the latter the subject of a particularly wry account in Partridge. Partridge liked to set himself against the OED, which had been above recording many of the usages that he documented (though hundreds of his explanations would duly find their way into the OED's second edition of 1989). Modern reference books owe much to his largely solitary endeavours, comparable to those of Samuel Johnson on his great Dictionary. His Dictionary of Slang and Unconventional English secured his reputation both as a lexicologist and as an eccentric, and he continued revising it at intervals for the rest of his life. Somewhat miraculously, and with considerable ingenuity, he managed to earn his living by writing. He wrote rather unsuccessful novels and plenty of reviews, as well as his many works on the English language. He abandoned what seemed a perfectly promising academic career for life as what he called "a man of letters". His first language book was Songs and Slang of the British Soldier (1930), and his dictionary is especially rich in military slang, most of which now has an antique ring. He had served in the Australian army in the first world war (at Gallipoli and on the western front). He was born in New Zealand and educated largely in Australia, coming to Britain on an academic fellowship in his late 20s. Partridge himself came from outside the borders of standard English. As David Crystal points out in an affectionate foreword to this new edition, even when Partridge was working on his magnum opus in the 1920s and 30s, slang was beneath the horizon of most writers on the English language, and was present only at the edge of modern dictionaries. He had the somewhat impatient confidence of a pioneer. The strength and weakness of Partridge's lexicon was always his willingness to include his opinions in what presented itself as a work of reference. The entry is like a vivid, compacted little essay, rich in hunches and associations. He noted the Norwegian cognate slenjakeften ("to sling the jaw, to abuse") and cited examples of the language-slinging of hawkers and thieves.
Partridge characteristically observed that the Oxford English Dictionary hazarded no etymology, but that did not stop him having "little doubt" that the upstart word derived from "sling". It was one of those many improper words for something rather unpleasant (like "mob" or "slum") that itself became proper. It seems to have appeared in the mid-18th century and forced its way into standard English by the 1860s.
The entry on the word in Eric Partridge's original 1937 edition of his extraordinary one-man dictionary reaches back towards its obscure origins as a vulgar term for "the special vocabulary (eg cant) of low, illiterate, or disreputable persons low illiterate language". Once, "slang" was itself slang - a specimen of the very thing that it described. A Dictionary of Slang and Unconventional English, 8th edition